Conventionally, of thermoplastic resins, a polar group-containing polymer such as a polyester and a polyamide is particularly excellent in mechanical strength, heat resistance, gas barrier properties and the like, and is therefore used as various molded articles such as a container, a palette, a gas tank, a civil engineering material and a precision machine. Further, in recent years, utilization of a recyclable product such as a polyethylene terephthalate, and utilization of an environment adaptive biodegradable resin such as a polylactic acid are advancing. However, as the defect of those polar group-containing polymers, it has been taken that impact resistant strength is poor.
For the purpose of improving impact resistance, a compound comprising a polar group-containing polymer having blended therewith a polycarbodiimide and various elastomers and the like is already known (see Patent Document 1 and Patent Document 2). Patent Document 1 discloses that by using a thermoplastic polyester and a polycarbodiimide as a graft-coupling agent to an amine-functionalized elastomer, a polyester composition having high impact resistance is obtained. Further, Patent Document 2 discloses that a resin composition comprising a thermoplastic resin and a polycarbodiimide is blended with a modified polyolefin or the like, and the resin composition obtained is excellent in impact strength. However, by merely blending a polar group-containing polymer such as a polyester, a polycarbodiimide, and various elastomers, improvement in its impact strength cannot yet be satisfied. In particular, with respect to impact strength at low temperature such as −10° C. or −40° C., further improvement was desired. Further, in the case of conducting molding such as an injection molding from a composition in the case of merely blending, surface of a molded article generates burrs, or is rough, and it was difficult to obtain a smooth surface.
Patent Document 1: JP-T-08-508530 (the term “JP-T” as used herein means a published Japanese translation of a PCT patent application)
Patent Document 2: JP-A-09-194719